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%I #14 Jan 20 2024 16:14:49
%S 1,2,2,3,4,5,5,6,7,8,8,9,10,10,11,12,13,13,14,15,16,16,17,18,19,19,20,
%T 21,21,22,23,24,24,25,26,27,27,28,29,30,30,31,32,32,33,34,35,35,36,37,
%U 38,38,39,40,40,41,42,43,43,44,45,46,46,47,48,49,49,50,51,51,52,53,54
%N a(1)=1; for n >= 2, a(n) = n - floor((1/2)*a(a(n-1))).
%H Michel Dekking, <a href="/A138466/a138466.png">Proof by Benoit Cloitre</a>
%F For n >= 1, a(n) = floor((sqrt(3)-1)*(n+1)).
%t Floor[(Sqrt[3] - 1)*(Range[100] + 1)] (* _Wesley Ivan Hurt_, Jan 20 2024 *)
%o (PARI) a(n)=floor((sqrt(3)-1)*(n+1))
%Y Cf. A005206, A138467, A160390.
%K nonn,easy
%O 1,2
%A _Benoit Cloitre_, May 09 2008
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